A mechanically enhanced metal-organic framework/PDMS membrane for CO2/N2 separation

Abstract

Interface compatibility is crucial to performance and robustness of nanocomposite membranes for molecular separation. In this work, a covalent crosslinking method was exploited to fabricate polydimethylsiloxane/metal-organic-frameworks (PDMS/MOFs) mixed matrix membranes with improved interfacial compatibility. Zirconium MOF particles (UiO-66-NH2) were grafted with methoxysilane groups, which further formed covalent crosslinks with silanol terminated PDMS matrix. The strengthened interfacial compatibility prevented sedimentation and aggregation of MOF particles in PDMS precursor solution during the solvent evaporation process, thus the composites showed good membrane formation ability at high MOFs loading (60 wt%). Tensile strength of the hybrid membrane is 2.8 times improved while retaining good flexibility. Moreover, the CO2/N2 selectivity and CO2 permeability of the PDMS composite membrane incorporated with 40 wt% UiO-66-MS particles are improved by 1.3 times and 0.7 times, respectively.